1. Field of the Invention
This invention relates to a storage control unit having a plurality of control devices connected to a plurality of disk devices, and method of transferring replication logical volumes thereof.
2. Description of the Prior Art
As a virtualization art concerning logical volumes of a storage control unit, there is an art of managing logical units (LU) of an external storage control unit, which is of a different frame from the unit, inside the storage control unit. See, for example, Japanese Patent Application Laid-Open (Kokai) Nos. H7-210439, 2001-318833 and 2003-008821. There are also arts for creating replications of logical volumes inside a storage control unit.
In recent years, a concept called “storage grid,” with which a plurality of distributed computing resources are put into operation as a single entity, is becoming noted in the storage industry. As one form thereof, a configuration may be considered wherein a plurality of storage control units are arranged together and deemed to be a single system. Presently, the data in replication logical volumes (including relevant volumes, such as those of the same attribute, etc.) in a storage control unit cannot be transferred with the relevance being maintained to other storage control units in accompaniment with an increase or decrease of the number of storage control units or for the purpose of load distribution between and among storage control units. Furthermore, in cases where the abovementioned storage control units are connected to an external storage control unit, logical volume transfer processes between and among storage control units cannot be performed likewise for replication logical volumes that are entities in the external storage control unit.
This invention has been made in view of the above issues and aims to provide in a storage system comprising a plurality of storage control units, a means for transferring replication logical volumes (including those with which the logical volume entities exist in an external storage control unit) between and among storage control units.